https://wiki.hydrogenaud.io/api.php?action=feedcontributions&user=Foot&feedformat=atomHydrogenaudio Knowledgebase - User contributions [en]2024-03-28T14:13:15ZUser contributionsMediaWiki 1.22.7https://wiki.hydrogenaud.io/index.php?title=Topic_IndexTopic Index2005-08-21T02:07:45Z<p>Foot: /* Windows */</p>
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<div>* Please see [http://www.hydrogenaudio.org/forums/index.php?showtopic=12979&st=25&p=247441&#entry247441 this thread] for a discussion of the future structure of this wiki. If you have thoughts, comments, suggestions, etc., please join in this discussion. In the meantime, please feel free to fill in gaps in the information below.<br />
* See also [http://www.hydrogenaudio.org/forums/index.php?showtopic=28658 style related discussion]<br />
<br />
<br />
==General Information==<br />
<br />
===General Guides===<br />
* [[Create a long-term archive]]<br />
* [[Enabling DMA]]<br />
===EAC Guides=== <br />
* [[Create a lossless back-up with EAC and Flac]]<br />
* [[EAC and Lame | Configuring EAC and Lame]]<br />
* [[EAC_and_Ogg_Vorbis | Configuring EAC and Vorbis]]<br />
* [[EAC_and_WavPack | Configuring EAC and Wavpack]]<br />
* [[EAC_and_Flac | Configuring EAC and FLAC]]<br />
* [[EAC_and_Monkeys_Audio | Configuring EAC and Monkey's Audio]]<br />
<br />
===CDex Guides===<br />
===MP3 Guides===<br />
<br />
* [http://wiki.hydrogenaudio.org/index.php?title=LAME Recommended settings for encoding with LAME]<br />
<br />
===Ogg Vorbis Guides=== <br />
<br />
* [http://wiki.hydrogenaudio.org/index.php?title=Recommended_Ogg_Vorbis Recommended encoders and settings for encoding with Vorbis].<br />
<br />
==Audio Codecs==<br />
<br />
===[[Lossy]]===<br />
*[[AAC]]<br />
*[[AC3]]<br />
*[[ATRAC3]]<br />
*[[DTS]]<br />
*[[MP2]]<br />
*[[MP3]]<br />
*[[Musepack]]<br />
*[[Ogg Vorbis]]<br />
*[[QDesign]]<br />
*[[VQF]]<br />
*[[WMA]]<br />
<br />
===[[Lossless]]===<br />
<br />
*[[ALAC|Apple Lossless]]<br />
*[[FLAC|Free Lossless Audio Compressor]]<br />
*[[LA|Lossless Audio]]<br />
*[[LPAC]]<br />
*[[Monkey's Audio]]<br />
*[[OptimFROG]]<br />
*[[RealAudio Lossless]]<br />
*[[Shorten]]<br />
*[[TTA|True Audio]]<br />
*[[WavPack]]<br />
*[[WMA|WMA Lossless]]<br />
<br />
===[[Metadata]] (Tags)===<br />
* [[APEv1]]<br />
* [[APEv2]]<br />
* [[ID3v1]]<br />
* [[ID3v1.1]]<br />
* [[ID3v2]]<br />
* [[Vorbis Comment]]<br />
<br />
==Media Extractors==<br />
<br />
===CD Extractors===<br />
<br />
* [[Exact_Audio_Copy|Exact Audio Copy]] (Win32)<br />
* [[iTunes]] (Win32/OsX)<br />
* [[CDex]] (Win32)<br />
* [[cdparanoia]] (Posix)<br />
* [[Grip]] (Posix) <br />
* [[PlexTools]] (Win32)<br />
* [[dBpowerAMP with AccurateRip]] (Win32)<br />
<br />
===DVD Extractors===<br />
* [[DVDDecrypter]] (Win32)<br />
<br />
<br />
==Media Players==<br />
<br />
=== Windows ===<br />
<br />
* [[Apollo]]<br />
<br />
* [[dBpowerAMP]]<br />
<br />
* [[Foobar2000:Foobar2000|foobar2000]]<br />
<br />
* [[iTunes]]<br />
<br />
* [[musikCube]]<br />
<br />
* [[Quintessential Player]]<br />
<br />
* [[VUplayer]]<br />
<br />
* [[Winamp]]<br />
<br />
* [[Windows Media Player]]<br />
<br />
* [[wxMusik]]<br />
<br />
* [[XMPlay]]<br />
<br />
===Linux/BSD===<br />
<br />
* [[Amarok]]<br />
<br />
* [[BMP]]<br />
<br />
* [[JuK]]<br />
<br />
* [[LAMIP]]<br />
<br />
* [[Muine]]<br />
<br />
* [[Music Player Daemon (MPD)]]<br />
<br />
* [[Rhythmbox]]<br />
<br />
* [[wxMusik]]<br />
<br />
* [[XMMS]]<br />
<br />
===Mac OS X (Non-BSD Specific) ===<br />
<br />
* [[iTunes]]<br />
<br />
* [[skiTunes]]<br />
<br />
* [[Whamb]]<br />
<br />
===Other===<br />
<br />
* [[CL-Amp]] (BeOS)<br />
<br />
<br />
==Audio Editors==<br />
<br />
=== Windows ===<br />
<br />
* [[Adobe_Audition|Adobe Audition]] (Previously known as Cool Edit)<br />
* [[Audacity]]<br />
* [[Goldwave]]<br />
* [http://www.sonymediasoftware.com/products/soundforgefamily.asp Sony Sound Forge] (Previously released by Sonic Foundry)<br />
<br />
===Linux/BSD===<br />
<br />
* [[Audacity]]<br />
* [[ReZound]]<br />
<br />
===Mac OS X (Non-BSD Specific) ===<br />
<br />
* [[Audacity]]<br />
<br />
===Other===<br />
<br />
<br />
==Testing Software==<br />
<br />
===Subjective Perceptual===<br />
<br />
* [[ABC/HR]]<br />
<br />
* [[PCABX]]<br />
<br />
===Objective===<br />
<br />
''Note: Might be good to put something here about the problems of quality comparisons using graphs, frequency sweeps, etc.''<br />
<br />
* [[EAQUAL]]<br />
<br />
* [[Rightmark_Audio_Analyzer|Rightmark Audio Analyzer]]<br />
<br />
<br />
==Audio Hardware==<br />
<br />
===PC Audio===<br />
<br />
*[[Terratec EWX 24/96]]<br />
*[[M-Audio Audiophile 24/96]]<br />
*[[M-Audio Revolution 5.1]] <br />
*[[Emu 0404 24/96]] <br />
*[[Emu 1212M 24/192]]<br />
*[[Audiotrak MAYA 5.1]] <br />
*[[Audiotrak Prodigy 7.1]]<br />
<br />
===Notebook Audio=== <br />
*[[Echo Indigo IO 24/96]]<br />
<br />
===HiFi===<br />
<br />
===Digital Audio Players===<br />
<br />
'''Portable Flash'''<br />
<br />
''(These players make use of a internal flash drive.)''<br />
<br />
* [[Creative MuVo]]<br />
<br />
* [[iRiver iFP Series]]<br />
<br />
* [[MPIO lFP Series]]<br />
<br />
* [[Rio Carbon]]<br />
<br />
* [[Neuros]]<br />
<br />
* [[Apple iPod shuffle]]<br />
<br />
'''Portable HD'''<br />
<br />
''(These players make use of a internal harddrive.)''<br />
<br />
* [[Apple iPod]]<br />
<br />
* [[iRiver H-Series]]<br />
<br />
* [[MPIO H-Series]]<br />
<br />
* [[Rio Karma]]<br />
<br />
* [[iAudio M3]]<br />
<br />
* [[Neuros]]<br />
<br />
* [[Archos Jukebox with Rockbox Software]]<br />
<br />
'''Portable CD'''<br />
<br />
'''Car Players'''<br />
<br />
''(Car stereos that can read MP3, Vorbis, WMA, etc.).''<br />
<br />
* [[Aiwa CDC-MP3]]<br />
<br />
==Audio Theory==<br />
<br />
===Analog Audio===<br />
<br />
===Digital Audio===<br />
* [[Replaygain]]<br />
<br />
===Testing Methodology===<br />
<br />
* [[ABX]]<br />
* [[EAQUAL]]<br />
<br />
==Audio Development==<br />
<br />
===Getting Started===<br />
''note: Let's start with basic development tools (compilers, engineering tools, dev. libraries) until we think of more tools to add. I am also adding external links to books, tutorials, etc under resources.''<br />
<br />
===Tools===<br />
<br />
* [http://www.mathworks.com/products/matlab/ MATLAB 7.0] commercial software for algorithmic design, developement, engineering, and scientific computing.<br />
* [http://www.octave.org/ GNU Octave] open-source alternative software (GPL) to MATLAB for numerical computations, engineering, and scientific computing. (multi-platform support)<br />
* [http://www.fftw.org/ FFTW] Is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions on real and complex inputs.<br />
* [http://gcc.gnu.org/ GCC] THE GNU compiler collection for C, C++, Objective-C, Fortran, Java, and Ada.<br />
* [http://www.bloodshed.net/devcpp.html DevCPP] free front-end IDE and compiler for the C and C++ languages. Delphi and C source code available.<br />
<br />
===Resources===<br />
<br />
* [http://www.hydrogenaudio.org/forums/index.php?showforum=30 Scientific/R&D Forums] for Psychoacoustic, DSP, Electrical Engineering, theory, and coding related questions. (most questions are generally answered)<br />
* [http://www.aes.org/ AES] The Audio Engineering Society website. Home of year-round world AES conferences.<br />
* [http://www.dspguru.com/info/books/favor.htm DSP Tutorials] this site provides another good introduction in to the area of DSP. <br />
* [http://www.musicdsp.org/archive.php?classid=2 Music-DSP] source-code archive for anaylsis, filters, effects and synthesis. (C, C++, and Java code)<br />
* [http://www.alsa-project.org/ ALSA Project] (Advanced Linux Sound Architecture) bringing audio and MIDI capabilities to Linux.<br />
* [http://perso.wanadoo.fr/polyvalens/clemens/wavelets/wavelets.html A Really friendly guide to Wavelets] A good introduction to wavelets aimed towards engineer, requires a fair amount of background knowledge.<br />
<br />
===Books/Research=== <br />
* [http://www.springeronline.com/sgw/cda/frontpage/0,11855,5-0-22-1437236-0,00.html?referer=www.springer.de%2Fcgi-bin%2Fsearch_book.pl%3Fisbn%3D3-540-65063-6 Psychoacoustics - Facts and Models] author's Zwicker, Fastl, and Hugo, revised 1999 second edition. THE book for comprehensive psychoacoustics models and figures. <br />
* [http://www.dspguide.com/ Scientist and Engineer's Guide to DSP] author Steve Smith, a great guide for beginners new to the subject of DSP (free online text)<br />
* [http://www.eas.asu.edu/~spanias/papers/paper-audio-tedspanias-00.pdf Perceptual Audio Coding] authors A. Painter and T. Spanias. Comprehensive paper on percepual audio coding (PDF)<br />
<br />
==Audio Resources==<br />
<br />
===Websites===<br />
<br />
''Note: Let's include a small description to the side for now, so that we have something to work with when this section becomes large enough for its own page''<br />
<br />
* http://www.audiocoding.com (Page with a wiki on technical audio topics, homepage of FAAC and FAAD2, also has an AAC forum.)<br />
* http://www.ff123.net (Lots of general information on various MP3 implementations, test samples, testing methodology information, homepage of ABC/HR)<br />
* http://www.head-fi.org (general information/board about head phones and portable audio players)<br />
* http://www.rarewares.org (Downloads for many audio and media tools)<br />
<br />
===Articles===<br />
<br />
===Listening Tests===<br />
* [http://www.rjamorim.com/test/ Roberto's listening tests]<br />
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=35438&st=0 Guruboolez listening test]<br />
<br />
==Other Topics==<br />
<br />
===Video===<br />
<br />
* [[MPEG-4 Visual]]<br />
* [[Theora]]<br />
* [[Real Video]]<br />
* [[Windows Media Video]]<br />
* [[VP6]]<br />
<br />
===[[Container format]]s===<br />
* [[AVI]]<br />
* [[MP4]]<br />
* [[MOV]]<br />
* [[ASF]]<br />
* [[Matroska]]<br />
* [[Ogg]]<br />
<br />
==Glossary==<br />
<br />
* [[Glossary_Of_Audio_Terms|Glossary of Audio Terms]]</div>Foothttps://wiki.hydrogenaud.io/index.php?title=HarmonicsHarmonics2005-08-21T02:03:33Z<p>Foot: </p>
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<div>Harmonics are vibrations at frequencies that are multiples of the fundamental. They are characterized as even-order and odd-order harmonics. For instance, the "second-order harmonic" is the fundamental [[frequency]] multiplied by two, and is an even-order harmonic. Each even-order harmonic is one octave or x octaves higher than the fundamental; they are therefore musically equivalent to the fundamental. Odd-order harmonics create a series of notes that are musically related to the fundamental [[frequency]]&mdash;unparallel but resonant with the fundamental, they inform musical scales and give rise to Chords. Harmonics are also called "overtones" or "partials".</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Glossary_Of_Audio_TermsGlossary Of Audio Terms2005-08-21T01:57:41Z<p>Foot: /* F */</p>
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<div>==A==<br />
<br />
* [[AAC]]<br />
* [[ABR]]<br />
* [[ABX]]/[[ABX|ABX testing]]<br />
* [[AC3]]<br />
* [[Aliasing]]<br />
* [[AltPresets]]<br />
* [[Ambisonics]] <br />
* [[Amplitude]]<br />
* [[APE]] ([[Monkey's Audio]])<br />
* [[APE Tags]]<br />
* [[Artifact]]/[[Artifact|Distortion]]<br />
* [[ATH]] (Absolute Threshold of Hearing)<br />
* [[ASPI]] (CD-ROM Installation)</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Digital_Signal_ProcessorDigital Signal Processor2005-08-21T01:36:14Z<p>Foot: </p>
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<div>DSP is an acronym for "Digital Signal Processor." A DSP microchip is a more specialized chip than a multipurpose CPU (i.e., a Pentium 4) and is optimised to perform certain signal processing mathematics very quickly.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Digital_Signal_ProcessorDigital Signal Processor2005-08-21T01:35:04Z<p>Foot: grammar rearrangement</p>
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<div>DSP means either "Digital Signal Processor." A DSP microchip is a more specialized chip than a multipurpose CPU (i.e., a Pentium 4) and is optimised to perform certain signal processing mathematics very quickly.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Digital_Signal_ProcessorDigital Signal Processor2005-08-21T01:32:11Z<p>Foot: typo</p>
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<div>DSP means either "Digital Signal Processing" or "Digital Signal Processing Microprocessor". DSP-processor is a more specialized chip than "CPU" like a Pentium 4. DSP-chip is optimised to perform very quickly certain signal processing mathematics.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Digital_Rights_ManagementDigital Rights Management2005-08-21T01:31:26Z<p>Foot: </p>
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<div>[http://www.eff.org/IP/DRM/ EFF's DRM page]</div>Foothttps://wiki.hydrogenaud.io/index.php?title=DCT_coefficientDCT coefficient2005-08-21T01:28:37Z<p>Foot: typo etc.</p>
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<div>DCT coefficient presents the [[frequency|amplitude]] of a specific cosine basis function.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=DC_coefficientDC coefficient2005-08-21T01:27:52Z<p>Foot: typography enhancement.</p>
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<div>DC coefficient is the [[DCT]] coefficient for which the [[frequency]] is zero in both dimensions.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=CodecCodec2005-08-21T01:25:31Z<p>Foot: typography enhancement.</p>
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<div>'''Codec''' stands for '''co'''der/'''dec'''oder or '''co'''mpression/'''dec'''ompression algorithm. A codec is used to encode and decode different types of data, such as audio or video signals. Examples are [[MP3]] audio or mpeg-4 video (see [[MPEG-4 Visual]]). Codecs can be used with both [[Streaming]] (live video or audio) or file-based (e.g. avi, wav) content.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Blind_testBlind test2005-08-21T01:17:49Z<p>Foot: opening paragraph clarification</p>
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<div>The concept of blind test was first introduced in medicine, in order to determine the effect of drugs on test subjects without coloring the results with subjective responses from both the subjects and experimenters.<br />
<br />
A blind medical test is a test where the patient doesn't know if he is taking a real product or placebo pills.<br />
<br />
A double blind medical test is a test in which the patient doesn't know if he is taking a real product or placebo pills, nor does the physician who gives them to him.<br />
<br />
Such tests are required in order to prove that when someone takes a new product, the product itself has an action on the disease, and that if a healing occurs, it is not completely caused by the natural defenses of the human body or by the [[placebo]] effect.<br />
<br />
In order to adapt this definition in audio, we can say that:<br />
<br />
A blind listening test is a listening test in which the tester doesn't know what source he is listening to.<br />
<br />
A double blind listening test is a test in which nobody in the room know which source is being played.<br />
<br />
Blinds listening tests are required in order to eliminate any [[bias]] that would lead the listener to prefer one source over another for personal reasons or preferences, that would have nothing to do with the sound. People also often imagine hearing differences between, say, a [[CD]] and an [[MP3]] coming from this CD, just because knowing that they are listening to an MP3 disturbs them. When the test is blind, the listener doesn't know if he is listening to a CD or an MP3, so he can't tell that the MP3 sounds bad just because he doesn't like MP3. It can only tell it if it does sound bad. In [[Hydrogenaudio]], we use blind test mostly in order to judge the sound quality of codecs, but they can also be used to listen to any piece of audio device. The prefered tests for audio codecs are [[ABX|ABX tests]].<br />
<br />
Double blind tests are prefered in medicine. There are evidences that when the physician knows what he is giving, the effect on the patient is affected. The situation in audio tests is a bit different, but a double blind test is always more rigorous than a simple blind test, because any influence from the operator on the listener is ruled out.<br />
<br />
Setting up double blind listening tests is very difficult in hifi. Either it requires very much money, for example to compare two amplifiers, 8 hidden units of each model would be connected to a switch, and no one in the room would know which of the 16 possible sources is what. Either it is very complicated and time consuming: in order to switch between the two amplifiers, the listeners would have to leave the room, and the operator would come in, close the door, choose to switch or not the devices, leave, and tell the listeners to come in again.<br />
<br />
Fortunately, if we compare codecs on a computer, double blind tests are very easy to perform. When a program like [http://ff123.net/abchr/abchr.html ABC/HR] plays a random file for us to identify, since we have no way to know if it is the original file or the encoded file, we can say that the test is double blind.</div>Foothttps://wiki.hydrogenaud.io/index.php?title=Channel_couplingChannel coupling2005-08-21T01:12:19Z<p>Foot: tag fix</p>
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<div>Channel coupling is a method used to reduce [[bitrate]] demand by coding the stereo channel information more efficiently. there are several channel coupling methods. In mp3 the general term is [[joint stereo]].<br />
<br />
[[MP3]] can use 2 different channel coupling methods: mid/side-coding and [[intensity stereo]]. Mid/Side-coding calculates a "mid"-channel by addition of left and right channel (l+r)/2 and a "side"-channel (l-r)/2. With more mono-like signals one can use less [[bitrate]] to encode the side-channel, so that the overall bitrate will be less than encoding the left and right channel. Intensity stereo destroys phase information, so it's used only at low bitrates.<br />
<br />
Correctly implemented MP3 mid/side stereo (like in [[LAME]]) does very little or no damage to the stereo-image and increases compression efficiency either by reducing size or increasing overall quality.<br />
<br />
[[Ogg Vorbis]] can use a mixture between 3 different types of channel coupling methods: phase stereo, [[point stereo]], and lossless. These are all based upon '''square polar mapping''' which is beneficial when the correlation between the left and right channels are strong (this can also be extended to multichannel coupling as well). Phase stereo is the "least agressive means" of quantization. It effects only "diffuse imaging" or ''(angle)'' information, due to the fact that the ear is least sensitive to [http://en.wikipedia.org/wiki/In_phase in-phase] or [http://en.wikipedia.org/wiki/Out_of_phase out-of-phase] noise above 4 kHz. Phase stereo is '''not''' curerently implemented in reference encoder due to complexity, but will be re-added again later on. [[Point stereo]] is a "more agressive means" of quantization. It eleminates the possibility of an out-of-phase signal ''entirely'' as to only have an effect of "point imaging" or ''(magnitude)'' information, hence the amplitude. It is currently used in the reference encoder on all modes below a -q 6. Lossless coupling just does polar mapping/channel interleaving using the residue vectors and has a bit-for-bit identical output. ''Note: also that phase stereo should not be compared to intensity stereo in MP3 coding'' <br />
<br />
Ogg Vorbis uses lossless/point stereo coupling below (''-q 6''). lossless channel coupling is used for high bitrates entirely (''-q 6 and up''). This can be adjusted via an advanced-encode switch, but is not done for simplicit sake.</div>Foot